Oral administration of a turmeric extract inhibits LDL oxidation and has hypocholesterolemic effects in rabbits with experimental atherosclerosis

Abstract

The oxidation of low-density lipoproteins (LDL) plays an important role in the development of atherosclerosis. Curcumin is a yellow pigment obtained from rhizomes of Curcuma longa and is commonly used as a spice and food colouring. Curcumin and turmeric extracts have several pharmacological effects including antitumour, anti-inflammatory, antioxidant and antiinfectious activities although the precise mechanisms involved remain to be elicited. We evaluated the effect of an ethanol-aqueous extract obtained from rhizomes of C. longa on LDL oxidation susceptibility and plasma lipids in atherosclerotic rabbits. A total of 18 rabbits were fed for 7 weeks on a diet containing 95.7% standard chow, 3% lard and 1. 3% cholesterol, to induce atherosclerosis. The rabbits were divided into groups, two of which were also orally treated with turmeric extract at doses of 1.66 (group A) and 3.2 (group B) mg/kg body weight, respectively. A third group (group C) acted as a control. Plasma and LDL lipid composition, plasma alpha-tocopherol, plasma retinol, LDL TBARS, LDL lipid hydroperoxides and analysis of aortic atherosclerotic lesions were assayed. The low but not the high dosage decreased the susceptibility of LDL to lipid peroxidation. Both doses had lower levels of total plasma cholesterol than the control group. Moreover, the lower dosage had lower levels of cholesterol, phospholipids and triglycerides in LDL than the 3.2-mg dosage. In conclusion, the use of this extract could be useful in the management of cardiovascular disease in which atherosclerosis is important.